Hey have you guys experience ABS failure on the track before? This is the second time it does this to me:


dont have a warning light, don’t have an error message. These are on pagid RS29’s front and rear

 

I know that ABS ice mode is a complaint on these cars, which I believe is where the pedal is hard initially and you don't get as much bite as you normally would, but if you go at the brakes again it will be fine. In your case this does look like the ABS system is just not working properly. I would definitely have this checked at a local shop or dealer, but I would be checking wheel speed sensors, yaw sensor, the ABS module itself and potentially even replacing the wheel bearing which I believe has reluctor rings inside of them.

I had the opposite problem on my C2S where ABS would come on during basically every drive in random driving situations. Everything from backing out of the driveway to just stopping when approaching a light. I ended up selling the car as basically everything was replaced including the module itself with no luck.

I would want to know additional info though, did this only start happening with those pads? Did you track it on stock pads and not have this issue? Looks like you have a 997.2, so you would have center locks? Or did you replace them with 5 lugs? I am wondering if something during that swap could have caused an issue.

 

Yes think it’s only happened with these pads though they are a fairly common pad choice.

stock center locks

gyrodisk front rotors stock rears stock calipers

tryibg ro figure out if this has happened to someone before. Again, it’s done it the last two times I tracked the car.

 

I don’t think that’s ice mode kicking in as the abs still stops wheel lockup in that case.
Are you getting total four wheel lockup?

 

No. Unfortunately the lock up is in the rear.

I guess I am trying to find out from those that track their cars if this has happened to them.

If not, then I have an issue. Though its unfortunate I dont have a warning light or fault code.

 

I tracked my 997.1 and 997.2 RSes hard in the day. Braked like a leadfoot and wore three sets of PCCBs to prove. Never encountered anything like your vid.

At the minimum you need your ABS unit checked.

 

Thanks for response. Yep agreed. Wish I had a warning light.

 

can you post about 10 seconds before the event in the video ?

Also, with your solo, are you logging inputs on brake pressure, wheel speeds, etc? If so post those, let's see what is going on. If you don't know how to do that you can send me your session data files and let me know the time of the event int he session and I can see if I can find it.

You're SURE there was nothing on the track or other funkiness?

This is not ice mode. I've had that a bunch and am a pro at driving through it now LOL.

Thanks

 

I could but nothing there.

Just running into t7. Straight braking zone.

Nothing on track that I could see.

I had the solo configured to be logging from the ECU. Looked at data briefly last night and brake pressure logs strangely on Solo. Basically gives me on and off. Didn't look at wheel speeds but can pull those and post them or send them.

 

Ok forgot, 997 I think is only on or off, but thats ok.

In racestudio, assuming you have all these captured: graph brakes, throttle, individual wheel speeds, lat G, long G, steering inputs, speed
For only the event and slightly before and after

If you can get it all you'll have 10 individual graphs over a time scale of about 10-15 seconds.

 

I had a 997.2 GT3 do the same thing. The wrong CAN setup was selected in the AIM SOLO.

Chris Cervelli
Cervelli Technical Service

 

checked data and three wheels locked up: The only that did not was FL.

 

are you able to post the graphs with the other data points?

 

 

Had this issue on a converted 997s. Couple conclusions: Brake pad compound had incorrect initial bite primarily early in the session before the brakes reached optimal temps. My theory was that the fronts were biting more than the rears in those conditions so the wheel speeds were out of the acceptable range front to rear so the ABS shuts it's self off since its wheel speed dependent. Issue only occurred in heavy straight line braking areas. Another area that I found that contributed to the issue was the rotor thickness. I initially thought I solved my ABS issues when I replaced the rear rotors, which were just out of thickness spec, but the pads remained the same. The problem came back a few track days later. The ultimate solution was switching to a less aggressive pad, Pagid Rs19. RS19 has less initial bite then the RS29 that you're using. If its not happening all the time then I wouldn't be too concerned about your ABS unit. During my saga I replaced all the wheel speed sensors & wheel bearings chasing the issue & for peace of mind, but it was the pads all along!